an introduction to part 2

... France in the Middle Ages 20 5 18 Lines of Trade and Mediæval Towns 24 2 24 3 19 The British Isles 27 8 27 9 20 Treaty of Bretigny, 1360 28 7 21 French Possessions of the English King in 1 424 29 4 22 ... 29 4 22 France under Louis XI 29 8 29 9 23 Voyages of Discovery 349 24 Europe in the Sixteenth Century 358–359 25 Germany in the Sixteenth Century 3 72 373 26 The Swiss Confederation 422 27 Treaty ... history teaches Historians sometimes seem to forget this principle, when they claim to begin and end their books at precise dates We find histories of Europe from 476 to 918, from 127 0 to 14 92, ...

Ngày tải lên: 16/02/2014, 23:20

... Manifesto The reason is that there were two previous ones: • The Object-Oriented Database System Manifesto [20 .2, 25.1] • The Third Generation Database System Manifesto [26 .44] Like our own Manifesto, ... directly relevant to the topics at hand (End quote) The fact is, given the widespread availability and use of database systems today (on desktop and laptop computers in particular), many people ... Third Manifesto, as well as in the book itself As noted earlier, The Third Manifesto also includes a definition of Tutorial D──although, to be frank, there shouldn't be any need to refer to that...

Ngày tải lên: 06/08/2014, 01:21

... Defining backup and recovery procedures • Monitoring performance and responding to changing requirements This isn't an exhaustive list Copyright (c) 20 03 C J Date page 2. 6 2. 8 The file manager is that ... combination of a DC manager and a DBMS, in which the DBMS looks after the database and the DC manager handles all messages to and from the DBMS (or, more accurately, to and from applications ... system that manages stored files (it's "closer to the disk" than the DBMS is) It supports the creation and destruction of stored files and simple retrieval and update operations on stored records...

Ngày tải lên: 06/08/2014, 01:21

... end-oftransaction Any updates made to the database by the transaction in question are "rolled back" (undone) and are never made visible to other transactions • A set-level operation is an operation ... me more trouble than anything else in producing the eighth edition The 1999 standard is simultaneously enormous in size and extremely hard to understand (in this regard, you can get a sense of ... simple examples 4 .2 Overview SQL talks in terms of tables (and rows and columns), not relations (and tuples and attributes) SQL is often said to include both data definition and data manipulation facilities...

Ngày tải lên: 06/08/2014, 01:21

... operator and function To be specific, SQL uses function to mean an operator that's invoked by means of classical functional notation──or an approximation to that notation, at any rate!──and operator ... Update Operators The distinction between read-only and update operators──another logical difference!──becomes particularly important when we get to inheritance (Chapter 20 ) Prior to that point, ... (and they don't allocate any storage) It is very unclear as to (a) why SQL allows some types not to have an "=" operator and (b) why it allows the semantics of that operator to be user-defined when...

Ngày tải lên: 06/08/2014, 01:21

... the set of parts {P1,P2,P3,P4} and the set of parts {P1,P2,P3} and many other sets of parts as well (actually 60 others) Doesn't the Closed World Assumption thus require the relation to include ... or into integer and fractional parts) in suitable circumstances; so is a number atomic? What about bit and character strings, which are obviously decomposable? What about dates and times? And ... one ordering" doesn't mean we can't Copyright (c) 20 03 C J Date argument that "n ways to of operators" (and n = is Of course, "no tuple ORDER BY but it does page 6.5 mean the result of ORDER...

Ngày tải lên: 06/08/2014, 01:21

... syntactic and semantic) in the treatment of such operators between Tutorial D and SQL Note too the aggregate operators ALL and ANY, both of which operate on arguments consisting of boolean values; ... algebraic expression transformation rules mentioned in Chapter and discussed in detail in Chapter 18 An analogous remark applies to the answers to Exercises 8 .2 and 8.3 as well 8 .2 a Valid b Valid ... supplies some part and SB supplies part P# */ ( T2 TIMES T3 ) AS T6, /* T6 {SA,SB,P#} : SB supplies some part and SA supplies part P# */ Copyright (c) 20 03 C J Date page 7.17 ( T1 JOIN T2 ) AS T7,...

Ngày tải lên: 06/08/2014, 01:21

... Integrity has to with semantics or "business rules," and "business rules" can be arbitrarily complex; key constraints are just an important special case Copyright (c) 20 03 C J Date page 9 .2 ... We therefore need another extension to the original calculus (and algebra) The TCLOSE operator discussed briefly in Chapter is part of the solution to this problem (but only part) Further details ... SX.CITY 8.13 .20 { SX.S#, PX.P#, JX.J# } WHERE SX.CITY =/ PX.CITY AND PX.CITY =/ JX.CITY AND JX.CITY =/ SX.CITY 8.13 .21 SPJX.P# WHERE EXISTS SX ( SX.S# = SPJX.S# AND SX.CITY = 'London' ) 8.13 .22 SPJX.P#...

Ngày tải lên: 06/08/2014, 01:21

... TEACHER to OFFERING, ENROLLMENT to OFFERING, and OFFERING to COURSE are all properly maintained, the referential constraints from TEACHER to COURSE and ENROLLMENT to COURSE will be maintained automatically ... Nos 11 and 12, August 1st and 18th, 20 00, respectively) • Ron Ross (The Business Rule Book: Classifying, Defining, and Modeling Rules, 2nd edition, Business Rule Solutions LLC, 1997) (Not to mention ... parameters and the predicate is thereby reduced to a proposition──and that proposition is then required to evaluate to TRUE The parameters in question stand for relvars Don't get into it yet,...

Ngày tải lên: 06/08/2014, 01:21

... the LS tuple (S1,Smith ,20 ,London) to (S6,Green ,20 ,London) will succeed An attempt to update that same tuple (S1,Smith ,20 ,London) to either (S2,Smith ,20 ,London) or (S1,Smith ,20 ,Athens) will fail ... selfexplanatory Note: Examples to illustrate various specific rules are left in the book as an exercise No answer provided Restrict: Also self-explanatory Note: The subsection says: "An attempt to ... self-explanatory (though project is a little trickier than the operators covered prior to this point) Note: The subsection says: "An attempt to update the SC tuple (S1,London) to (S2,London)...

Ngày tải lên: 06/08/2014, 01:21

... formal, and it isn't very long, and it can probably just be skimmed if the instructor doesn't want to get too deeply into formal proofs and the like Indeed, the chapter is included, in part, just to ... from 20 to 30 by changing it once and for all in the relevant CS tuple 12. 3 1NF, 2NF, 3NF Mostly self-explanatory Another nice intuitive characterization of the normalization procedure: It's an ... began to panic: Where's this all going to end? Will there be a 6th, a 7th, an 8th, a 9th, a 10th, normal form? Will there ever be an end to this progression? Well, I'm pleased to be able to...

Ngày tải lên: 06/08/2014, 01:21

... your answer to Exercise 12. 7 to take this fact into account Answer: We don't give a full answer here, but remark that the techniques illustrated in the answer to Exercise 12. 5 are relevant 12. 8 ... as the decomposition operator and join as the recomposition operator 13 .2 MVDs and 4NF Mostly self-explanatory note: Possible points for the instructor to Copyright (c) 20 03 C J Date page 13.1 ... {EMP#,JOBTITLE}), and hence JOB1 isn't in 2NF We can replace it by JOB2A { EMP#, JOBTITLE } PRIMARY KEY { EMP#, JOBTITLE } and JOB2B { EMP#, DEPT# } PRIMARY KEY { EMP# } Copyright (c) 20 03 C J Date 12. 12 page...

Ngày tải lên: 06/08/2014, 01:21

... good rhetorical question: How would you represent an arbitrary join dependency in an E/R diagram? References and Bibliography References [14 .22 -14 .24 ] and [14.33] are recommended Answers to Exercises ... In particular, "entity types" at the semantic level almost certainly not map to "types"* at the formal level (forward pointer to Chapter 26 , Section 26 .2, if you like), and "entity supertypes and ... there are often to treat one -to- one and one -to- many relationships as in fact many -to- many You could augment or even replace the treatment of the E/R stuff, both in this section and in the next...

Ngày tải lên: 06/08/2014, 01:21

... theorem (important!) and the two-phase locking protocol If A and B are any two transactions in some serializable schedule, then either B can see A's output or A can see B's Copyright (c) 20 03 C J Date ... The idea is to allow an implementation to use some nonlocking scheme if it wants to. ) Explain phantoms and the basic idea (only) of predicate locking Mention access path locking as an implementation ... R1-R3-U1-U3-R2-U2 is serializable (it's equivalent to the serial schedule T1-T3T2), but it cannot be produced if T1, T2, and T3 all obey the two-phase locking protocol For, under that protocol, operation...

Ngày tải lên: 06/08/2014, 01:21

... "generating" operator for the whole of 2VL Can you find an operator that performs an analogous Copyright (c) 20 03 C J Date page 19.9 function for 3VL? 4VL? [19 .20 ] might help) nVL? No answers provided ... (c) 20 03 C J Date page 19.8 A AND NOT(A) AND B AND NOT(B) A NOT(A) B NOT(B) A OR B A AND B A OR NOT(B) A AND NOT(B) NOT(A) OR B NOT(A) AND B NOT(A) OR NOT(B) NOT(A) AND NOT(B) (NOT(A) OR B) AND ... answers Of course, it probably produces right answers too; but since we have no way of knowing which ones are right and which wrong, all answers become suspect) It's important to understand too...

Ngày tải lên: 06/08/2014, 01:21

... shorthand for a longer one, as we saw in the answer to Exercise 20 .9 20 .11 No answer provided 20 . 12 No answer provided *** End of Chapter 20 *** Copyright (c) 20 03 C J Date 20 .15 page Chapter 21 ... has DT(Y) equal to T, MST(Y) equal to MST(X), and v(Y) equal to v(X) 20 .3 No answer provided Copyright (c) 20 03 C J Date 20 . 12 page 20 .4 The least specific type of any value of any of the types ... Fig 20 .1 is PLANE_FIGURE, of course 20 .5 22 (this count includes the empty hierarchy) 20 .6 Since all rectangles are centered on the origin, a rectangle ABCD can be uniquely identified by any...

Ngày tải lên: 06/08/2014, 01:21

... [22 .3 -22 .5], [22 .10], [22 . 12] , [22 .16], [22 .25 ], [22 .28 ], [22 .30], and [22 .35] are not views but snapshots Annotation to those references talks in terms of snapshots, not views Copyright (c) 20 03 ... clumsy, and the arrays are 22 .10 No answer provided 22 .11 Perhaps Debate! Copyright (c) 20 03 C J Date page 22 .7 22 . 12 No answer provided *** End of Chapter 22 *** Copyright (c) 20 03 C J Date page 22 .8 ... 21 .3 See Section 21 .2 21.4 See Section 21 .4 21 .5 See Section 21 .4 21 .6 No answer provided 21 .7 No answer provided 21 .8 No answer provided *** End of Chapter 21 *** Copyright (c) 20 03 C...

Ngày tải lên: 06/08/2014, 01:21

... c ) AND J ( j, jn, c ) ? *═ RES ( p ) 24 .6 .25 Can't be done without negation 24 .6 .26 RES ( p1, p2 ) *═ SPJ ( s, p1, j1, q1 ) AND SPJ ( s, p2, j2, q2 ) ? *═ RES ( p1, p2 ) 24 .6 .27 -24 .6.30 Can't ... P ( p2, pn2, Red, pw2, pc2 ) k Can't be done without aggregate operators l S ( s, sn, st, London ) ═* SP ( s, P2, q ) m P ( p1, pn1, pl1, pw1, pc1 ) ═* P ( p2, pn2, Red, pw2, pc2 ) AND pw2 < 50 ... ( s, p, j, q ) AND SPJ ( s2, p, j2, q2 ) AND SPJ ( s2, p2, j3, q3 ) AND P ( p2, pn, Red, w, c ) ? *═ RES ( s ) 24 .6.36 RES ( s ) *═ S ( s, sn, st, c ) AND S ( S1, sn1, st1, c1 ) AND st < st1 ?...

Ngày tải lên: 06/08/2014, 01:21

... state and behavior; an instance of a class Instance: A concrete manifestation of an abstraction; an entity to which a set of operations can be applied and that has a state that stores the effects ... won't be relevant any more, and on and on Pretty strong claims for something that started out to be, in essence, nothing more than an approach to the data interchange problem! (To quote the XML ... reference [25 .24 ]; I would argue that that qualifier "powerful" should really be "complicated") 25 .6 No answer provided (it's straightforward, but tedious) 25 .7 No answer provided (ditto) 25 .8 No answer...

Ngày tải lên: 06/08/2014, 01:21

... along with an associated set of operators that can be applied to values and variables of the type in question (see Chapters and 20 for further Copyright (c) 20 03 C J Date 27 .19 page explanation) ... like this: 27 .21 { for $sx in document("SuppliersOverShipments.xml")//Supplier where document("PartsRelation.xml")//PartTuple Copyright (c) 20 03 C J Date 27 .22 page ... reference [27 .25 ]) It's really a metametalanguage (see Section 27 .4); that is, it's a language for defining languages for defining languages (these last being markup languages specifically) • An XML...

Ngày tải lên: 06/08/2014, 01:21